If you have installed a catless exhaust, your O2 sensors are why your light is on. The rear sensor has the same readings as the front one, and the computer is throwing a code and is trying to compensate which lowers your gas mileage. Do a search for Pony xpress, you can get it fixed for under $30.00.

i just talked to the guy i got my car form and he said that he got the fix for the sensor on the downpipe. he said that it was the up pipe that was causeing it. is there a fix for that? i most definetly want to fix this ezpecially if it's cause my gas milage to go down.

2.2k Ohm resistor - a 5% tolerance should be fine. There have been reports that a 1/4watt will go bad after a while, so you might want to get a 1/2watt resistor. The one that came with the Perrin though looked like a 1/4watt.